Fluorescent lamps energy efficient but with glitches
If households in Delhi replace four ordinary bulbs with four compact fluorescent lamps (cfls), their annual savings would be around Rs 273 crore. Startling figure. The highly energy inefficient incandescent light bulb is on its way out. Replacing it is the new-generation and more energy-efficient cfl (see box Energy efficient). Brazil and Venezuela initiated the process of phasing out incandescent bulbs. Australia plans to do it by 2010 and Canada by 2012. Other countries--New Zealand, Netherlands, us--are also planning to phase out incandescent bulbs.
In India, however, there is no formal plan to phase out ordinary bulbs yet. There is a debate over the amount of mercury that cfls may emit and concerns regarding its disposal.But pro-cfl groups say that mercury emissions from thermal-based power plants are much higher, compared to cfls and hence, the fears are unfounded. And, given the power crisis in the country, it is only feasible to convert to cfls (see box Advantage CFL).
However, there are advantages because cfls help in curbing greenhouse gases (see table Environmental pollution and resource consumption). Hence, the question that emerges is how will cfls impact the environment after they exhaust 7,000 hours of life? Calculations prove that mercury emission from cfls will be 4.32 times lower than incandescent ones, considering if electricity is supplied to incandescent bulbs by coal-based thermal power plants (see table 4.32 times lower). No laws for disposal and recycling of cfls, however, makes it tough. Given the scenario, there is the possibility of mercury spreading in the atmosphere. Coal-based thermal power plans also emit mercury--about 65 tonnes on an average through combustion of coal annually.
The emission of mercury from coal-based power plant, however, is point source (through chimneys). But controlling emissions from diffused sources (uncontrolled and random dumping) like cfl is a more difficult task. And it is anticipated that as the cfl-use goes up, the problem will assume alarming proportions. The solution, experts say, is to frame strict laws, give incentives for recycling and have buy-back policies in place. There should be written instructions on precautionary measures and ways of using and disposing cfls.
Technology exists to segregate glass, phosphor powder, mercury and other materials from expired cfls. Canada, for instance, has recycled 7 per cent of fluorescent bulbs. To reclaim mercury from fluorescent tubes, the tubes are placed on conveyer belts and crushed in a crusher. Then, after a series of stages, mercury is baked in a vacuum oven for up to 12 hours. It is then cooled, collected and sent for purification.
According to Delhi's electricity provider, bses, around 400,000 cfls have been distributed under the 'buy one, get one free cfl' scheme. Delhi has saved 25 mw. The scheme stared in October 2006. According to estimates, Delhi could save around 450 mw if ordinary bulbs are replaced by cfls. Not much reason why the rest of the country shouldn't follow the example, but with a proper disposal mechanism in place.
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